KABUL, Afghanistan, Feb. 23 (UPI) -- An Afghan soldier, apparently angry over the burning of Korans at a U.S. air base, fatally shot two U.S. troops and wounded four others, Afghan officials said.

The International Security Assistance Force said in a statement two military personnel were killed in eastern Afghanistan Thursday by "an individual wearing an Afghan National Army uniform" but didn't identify the troops' nationality.

CBS News said an Afghan official said the dead and wounded in the attack in the eastern province of Ningarhar were American. The official said the shooting seemed to be motivated by the burning of Korans at the Bagram Air Base north of Kabul, but did not elaborate.

Haji Mohammad Hassan, chief of Khugyani district in Ningarhar province, told CNN, "We don't know who started the shooting first and what kind of guns were used, but we have started our investigation to find out the details of the incident."